Autoimmune encephalitis should be excluded in unexplained encephalitis. A significant portion of autoimmune encephalitis in childhood is anti- NMDA encephalitis.However, neuroimaging and routine diagnostic tests are inadequate , diagnosis sholud be confirmed by the demonstration of autoantibodies. The treatment may be delay in this process.Extreme delta brush waves are unique EEG pattern, seen in some of Anti-NMDA encephalitis, useful for early diagnosis .Extreme delta brush activity is associated with prolonged hospitalization and illness. Despite of these the specificity and sensitivity of this pattern is not-known clearly.

We present a five years old boy with the loss of consciousness, involuntary movements, intermittant generalized tonic clonic seizures and extreme delta brush activity in EEG.